I. Field of the Disclosure
The technology of the disclosure relates generally to integrated circuits (ICs), and particularly to reducing magnetic coupling between components in an IC.
II. Background
Mobile communication devices have become common in current society. The prevalence of these mobile devices is driven in part by the many functions that are now enabled on such devices. Demand for such functions increases processing capability requirements and generates a need for more powerful batteries. Within the limited space of the housing of the mobile communication device, batteries compete with the processing circuitry. The competition for space for components and other factors contribute to a continued miniaturization of components within the circuitry.
Miniaturization of the components impacts all aspects of the processing circuitry including the memory transistors and other reactive elements in the processing circuitry. While miniaturization of components in mobile communication devices is easy for the consumer to appreciate as phones become smaller and lighter and have longer battery times, miniaturization pressures are not limited to mobile communication devices. Other computing devices such as desktop computers also try to increase available memory and processing power through miniaturization.
Concurrently with the miniaturization goals, the wireless communication industry continues to work towards providing as much bandwidth to consumers as possible. To this end, many wireless carriers have adopted carrier aggregation policies for current generation communications. That is, a wireless carrier such as AT&T® may own rights to two frequency bands (e.g., around 700 MHz and 2 GHz) in a particular geographic area. To maximize available bandwidth, the wireless carrier may use both frequencies simultaneously for a single communication stream. While using both frequency bands for a single communication stream does increase the amount of data that can be provided to the end user, there are complications in that each of the frequencies used to transmit data creates noise at the harmonic frequencies. In the AT&T® example, the 700 MHz transmissions create harmonics at 2.1 GHz that may interfere with data being broadcast at the 2 GHz frequencies. In such situations, a diplexer can be provided to process signals carried in a carrier aggregation system. In a chipset for a device using such a carrier aggregation system, the diplexer is usually inserted between an antenna and a tuner (or a radio frequency (RF) switch) to provide isolation between frequency bands to ensure high performance. Usually, a diplexer design includes inductors and capacitors for providing filtering. Diplexers can attain high performance by using inductors and capacitors that have a high quality (Q) factor. Diplexer performance may be quantified, by measuring the insertion loss and rejection (e.g., quantities expressed in decibels (dB)) at certain frequencies.
When miniaturization goals are applied to elements containing more than one inductor, such as diplexers, the inductors are frequently positioned in close proximity to each other. The close proximity of these inductors may result in magnetic coupling between the inductors. In most cases, this magnetic coupling results in a reduction in isolation and performance of the circuit.